Directory assistance, and more generally, the interrogation of a database via a telephony device, is currently achieved by using telephone operators to manually input data received in voice form from a user for interrogation of the database. The use of manual operators is generally preferred because they are more adept at interpreting voice input from enquirers than is voice recognition software. For example, the voice input may be made in a variety of accents and may be made over better or worse connections, and under these circumstances manual operators are generally preferred.
Furthermore, a manual operator is able to judge whether or not a word has been heard correctly so as to decide whether to ask a user to repeat the word or to carry out a search on the basis of the presumed input. The manual operator is also able to start the search and then to ask the user to give further information until the search is completed, or to decide that the search cannot be completed. Automatic methods of obtaining voice data lack the flexibility for making effective decisions in obtaining data and using the data in the search.
The use of human operators is the largest cost element attendant in running a telephony-based database enquiry service. Generally, the call volume varies with the time of day, with notable peak times. The use of human operators therefore requires considerable scheduling in order to meet peak demand.
Generally, a basic directory enquiry service is mandated by a telecommunications regulator, and value-added variations or improvements on the basic service may be provided as premium level services by the telecommunication service operator or by others.
Two particular known systems that address the above-mentioned problems include: (1) a rerouting system that routes calls to other call centers at peak times, and (2) an automation system that uses an automatic dialogue to obtain information from the caller. In the automation system, the recorded information is played back to an operator who may immediately initiate the search.
A further approach is to be described in U.S. Pat. No. 5,638,425, Meador et al, entitled “Automated Directory Assistance System Using Word Recognition and Phoneme Processing Method”, the contents of which are herein incorporated by reference. The patent discloses a mechanized directory assistance system for use in a telecommunications network, which includes multiple speech recognition devices comprising a word recognition device, a phoneme recognition device, and an alphabet recognition device. The system also includes a voice processing unit, and a computer operating under stored program control. A database is utilized which may comprise the same database as used for operator directory assistance. The directory assistance system operates as follows: A directory assistance caller is prompted to speak the city or location desired. The response is digitized and simultaneously inputted to the word and phoneme recognition devices, each of which outputs a translation signal plus a probability level signal. The probability level signals are compared and the highest probability level translation is selected. The caller is then prompted to speak the name of the sought party. The response is processed in the same manner as the location word. In the event that the probability level fails to meet a predetermined standard, the caller is prompted to spell all or part of the location and/or name. The resulting signal is inputted to the alphabet device. When translations are obtained having a satisfactory probability level the database is accessed. If plural listings are located from the database, then these listings are articulated and the caller is prompted to respond affirmatively or negatively to each listing. When a single directory number has been located, a signal is transmitted to the caller to articulate this number. The system also allows DTMF keyboard input in connection with the spelling procedure.